Gut Microbiota and Prognostic Outcomes in Intracranial Arterial Stenosis Patients（GROW-ICAS）

Inclusion Criteria: 1. Age 30-80 years. 2. Intracranial arterial stenosis confirmed by CTA/MRA/DSA. 3. Local residency ≥6 consecutive months. 4. Signed informed consent. Exclusion Criteria: 1. Tandem extracranial stenosis (≥50%) proximal to the target intracranial stenotic vessel. 2. Non-atherosclerotic intracranial stenosis. 3. Extracranial/intracranial endovascular treatment within 30 days pre-enrollment or planned intervention within 6 months. 4. Intracranial hemorrhage within 90 days pre-enrollment. 5. Pre-existing intracranial tumor, cerebral aneurysm, or arteriovenous malformation. 6. Cardioembolic embolism. 7. Active bleeding/hemorrhagic diathesis. 8. Major surgery within 30 days pre-enrollment or planned within 6 months post-enrollment. 9. Severe neurological deficits impairing independent living or dementia/psychiatric disorders hindering follow-up. 10. Pregnancy/lactation/planned pregnancy. 11. Chronic inflammatory/autoimmune diseases. 12. Uncontrolled hypertension or diabetes. 13. Severe cardiac/hepatic/renal dysfunction, hematologic disorders, malignancy, or life expectancy \<1 year. 14. MRI contraindications. 15. History of depression/anxiety/cognitive impairment requiring therapy. 16. Antibiotic/probiotic/glucocorticoid/immunosuppressant use within 1 month pre-enrollment. 17. Current/planned participation in other trials. 18. Inability to cooperate due to psychiatric/emotional disorders. 19. Other investigator-deemed ineligibility.